Field of the Invention
Embodiments of the invention generally relate to systems and methods for aligning an optical instrument at a desired spatial position relative to a target location such as, for example, the corneal apex of a human eye.
Description of the Related Art
Refractive surgery and other corrective procedures are commonly performed on the human eye. Such refractive surgical procedures are performed to improve the vision of the patient by altering select refractive properties of the eye (e.g., changing the curvature of the cornea, replacing select parts of the natural eye, such as the lens or the cornea, or by adding additional refractive elements to the eye). The surgeon's goal is to generally improve the overall vision of the patient as compared to the patient's pre-surgical visual state.
As part of the procedure, refractive measurements of the patient's eye are taken, usually both before and after surgery. A number of different devices currently exist by which the refractive measurements may be taken, such as wavefront aberrometers, phoroptors, corneal topographers, autorefractors, and keratometers. Of these, wavefront aberrometers generally provide the greatest detail about the refractive properties of the eye.
One important issue faced by many medical diagnosis optical systems is determining and/or maintaining a precise spatial relationship between the portion of the body undergoing diagnosis and the optical instrument. This is particularly true in the case of optical instruments, such as wavefront aberrometers, designed for measurement of properties of the eye. In many circumstances, determining a precise spatial relationship between the wavefront aberrometer and the eye allows for improved accuracy and precision in measurements performed by the wavefront aberrometer.